Microscopy

• The aim of the Microscopy practical is to use a light microscope to investigate a selection of plant and animal cells.
• The equipment required for the Microscopy practical includes a light microscope, microscope slide, cover slip, onion, forceps, iodine solution, white tile, scalpel, and any other prepared plant and animal cell slides.
• In the first step of the Microscopy practical, an epidermal layer on the onion is peeled off using forceps.
• The onion tissue is mounted onto the microscope slide with a drop of water using a pipette, making sure the tissue lies flat.
• Two drops of iodine solution are added to stain the cells.
• The cover slip is placed on by first placing one edge down on the slide and slowly lowering the other side of the cover slip using forceps.
• Excess stain is removed by soaking it with paper towels.
• The slide is placed on the stage of the microscope.
• The coarse adjustment knob is used to raise the stage until the cover slip just touches the objective.
• The fine adjustment knob is used to move the stage away until the image comes into focus.
• The nosepiece is turned to select a high power objective.
• The same process is repeated using a prepared slide.
• Safety precautions for the Microscopy practical include wearing safety goggles when handling the iodine solution.